Paul Remde wrote:
FLARM has become extremely popular in several regions of the world (Europe,
and Australia, and ...?), but it has not been "allowed" in the USA so far.
However, there are several gliders flying with FLARM here in the USA. It is
a great technology solution and safety enhancer. But technical and
liability hurdles exist here in the USA. Everyone that I've talked to that
uses FLARM in their glider loves it - especially in contests or at crowded
soaring sites, or along crowded ridges.

European FLARM operates in the 868.0 to 868.6 MHz range, Australian
OzFLARMs operate in the 915.0 to 928.0 MHz range. The legal range in
the US would be 902.0 to 928.0 MHz, and the combination of the
transmitter and antenna must be certified by the FCC.

European FLARMs are definitely illegal in the US, as they are smack in
the middle of the licensed commercial Specialized Mobile Radio (SMR)
band. If there is interference in that band (and an airborne
transmitter may interfere over a wide area), the FCC will mount a real
effort to track it down. OzFLARM may be legal, but only if the
transmitter is FCC certified, which includes limits on duty cycle which
the FLARM protocol may or may not meet.

- How do the FAA's plans to implement ADSB impact this discussion? In the
short run that looks like an extremely expensive solution for the aircraft
owner.

ADS-B is, in general, a better solution for US pilots, since it will
warn of glider vs. glider and glider vs. other aircraft collisions, and
will ultimately (~2020) be required for access to certain kinds of
airspace. Technically it is not all that much more difficult to
implement than FLARM. Certification requirements are far more onerous,
and the market for a low power unit suitable for gliders, balloons,
sport aircraft, etc., just doesn't exist at the moment. I suggest you
get someone in the room with ADS-B technical knowledge, like Bernald
Smith (who will almost certainly be at the convention) to discuss that
option...

Marc